The present invention relates generally to suspension systems and more particularly to a composite leaf spring with improved lateral stiffness for use in suspension systems.
A suspension system on an automobile works with the tires, frame or unit body, wheels, wheel bearings, brake system, and steering system to provide a safe and comfortable means of transportation. A suspension system has several important functions, including supporting the various components of an automobile, allowing the tires to move up and down to provide a comfortable ride, allowing for rapid cornering without extreme body roll, keeping the tires on the road surface, preventing excessive body squat when accelerating, preventing excessive body dive when braking, allowing the front wheels to turn side-to-side for steering, and, in combination with the steering system, keeping the wheels in correct alignment.
The suspension system uses springs, swivel joints, damping devices, and other components to accomplish these functions. The springs that are used within suspension systems have two primary functions. First, the springs should jounce (compress) and rebound (extend) when the tires encounter objects and holes in the road surface. The springs should also support the weight of the car while still allowing suspension travel (movement).
Leaf springs are commonly made of flat plates or strips of spring steel bolted together. Recently, fiberglass has shown potential to replace steel in longitudinal leaf springs because it significantly reduces weight. However, one disadvantage with these fiberglass leaf springs is that they generally tend to have less lateral stiffness as compared with comparable steel leaf springs.
It is thus highly desirable to provide a new leaf spring having the lateral stiffness of a steel leaf spring and the reduced weight of a fiberglass leaf spring while maintaining the vertical compliance and strength of a spring consisting of only fiberglass materials.
It is an object of the present invention to improve the lateral stiffness of a fiberglass leaf spring for use in a suspension system of an automobile while maintaining vertical compliance.
The above object is accomplished by replacing a small amount of glass fiber along the outer side edge of the fiberglass leaf spring with a small amount of carbon fiber. The amount and location of the carbon fiber replacing glass fiber within the leaf spring is controlled to improve lateral stiffness without significantly changing the vertical compliance and strength characteristics of the composite leaf spring.
The present invention uses manufacturing techniques commonly used in the textile or composite industry to produce the new composite leaf spring, thus new manufacturing processes do not need to be developed.
Other objects and advantages of the present invention will become apparent upon considering the following detailed description and appended claims, and upon reference to the accompanying drawings.